CN115340737A

CN115340737A - Improved SMA resin formulation

Info

Publication number: CN115340737A
Application number: CN202210610920.XA
Authority: CN
Inventors: E·凯利; T·K·王; R·F·泰森; C·G·小卡拉克
Original assignee: Isola USA Corp
Current assignee: Isola USA Corp
Priority date: 2016-07-25
Filing date: 2017-07-25
Publication date: 2022-11-15
Also published as: US20190270873A1; CN109790358B; KR20190034566A; US11365282B2; SG11201900686XA; TW201829606A; US11891475B2; WO2018022563A1; EP3487932A1; KR102414272B1; CA3032191A1; JP7046907B2; JP2019528338A; CA3032191C; US20230141772A1; TWI780060B; CN109790358A

Abstract

The present invention relates to a resin composition comprising at least two different inert fillers, which can be used for the preparation of prepregs and laminates for the manufacture of printed circuit boards.

Description

Improved SMA resin formulation

The application has the application date of 2017, 7 and 25, and the application numbers are as follows: 2017800461902, a divisional application of the invention patent application entitled "improved SMA resin formulation".

(1) Field of the invention

The present invention relates to resin compositions for impregnating woven materials which are then partially or fully cured to form prepregs and laminates for the manufacture of printed circuit boards. Prepregs and laminates prepared using the resin composition of the present invention have excellent electrical properties suitable for high frequency applications in electronic devices, as well as excellent thermal and mechanical properties.

(2) Background of the invention

Fillers such as talc can be an important component in the resins used to make prepregs and laminates that are subsequently used in the manufacture of printed circuit boards. Talc provides thermal stability, fills voids, and improves PCB drilling. Styrene Maleic Anhydride (SMA) is some of the resin components used to make prepregs and laminates. SMA may be included in the resin to improve the glass transition temperature (T) _g ). When used together in a resin system for PCB applications, talc and SMA can provide prepregs with improved thermal reliability under reflow (reflow). However, as the thermoelectric specifications of laminates and printed circuit boards continue to change, there remains a need for prepregs and laminates having improved thermal, electrical and mechanical properties.

Disclosure of Invention

Laminates for printed circuit boards and prepregs form a stack and ultimately a Printed Circuit Board (PCB) which includes a plurality of laminate layers bonded together. One problem that arises with PCBs is that adjacent laminate layers may delaminate (delaminanate), particularly when the laminate or PCB is subjected to high temperatures. Delamination may lead to circuit board failure. In addition, PCB manufacturers are also beginning to demand prepregs that can be used to manufacture PCBs with low wicking and white glass properties. Accordingly, there is a need for prepregs, laminates, resin-coated copper and similar resin-containing materials that can be used to form PCBs that are not easily delaminated and/or exhibit improved wicking and/or white glass characteristics.

In one aspect, we have found that the use of an unexpected combination of filler-silica and talc-provides a synergistic combination that better improves the electrical and/or thermal properties of certain laminates and/or PCBs as compared to the use of silica or talc alone. This is particularly true with anhydride curing agents.

Another aspect is a resin composition comprising a styrene maleic anhydride copolymer; at least one epoxy resin; at least one cross-linking agent; talc; and silicon dioxide.

Another aspect is a resin composition comprising: about 5 to about 40 weight percent, based on the dry, solvent-free resin, of a styrene maleic anhydride copolymer; about 10 to about 50wt%, on a dry, solvent-free basis, of at least one epoxy resin selected from the group consisting of brominated bisphenol a, brominated bisphenol F, non-brominated bisphenol a, non-brominated bisphenol F, and combinations thereof; about greater than 0 to about 20wt%, based on the dry, solvent-free resin, of at least one crosslinker selected from tetrabromobisphenol a, tetra-DOPO-bisphenol a, and mixtures thereof; about 2.5 to about 15wt% talc, based on dry resin; and about 2.5 to about 15 weight percent fumed silica on a dry resin basis.

Another aspect is a prepreg and/or laminate comprising a reinforcement material impregnated with a resin as described herein and a resin coated copper foil; the copper foil includes a copper foil having a first planar surface and a second planar surface, and a B-stage or C-stage resin layer as described herein applied to at least one of the planar surfaces.

Description of the present embodiments

The present disclosure relates generally to resins made from multiple components and prepregs and laminates including partially or fully cured resins.

The resins are prepared by a "compounding" process in which the resin ingredients are combined to form a thermoset resin. In one example, resin is used to make a laminate by "impregnating" a reinforcing material, such as a woven glass fabric, with the resin. In another example, resin is used to coat a copper foil to form a resin-coated copper laminate. In another example, the resin is used to form a laminate that does not include a reinforcing material. One type of product made using these resins is "prepregs", i.e., sheets that may include resin or resin impregnated reinforcement materials in which the resin is only partially cured or "B-staged". Another type of product made from resin is a C-staged laminate in which the resin is fully cured. The ingredients used to formulate the resin are discussed below. Unless otherwise indicated, component weight percent ranges are reported on a "dry" solvent-free basis.

The resin of the present invention comprises: (1) at least one SMA copolymer; (2) at least one epoxy resin; (3) at least one co-crosslinking agent; (4) talc; (5) fused silica; and a catalyst. The resin may include various optional ingredients including UV blockers, flame retardants, and solvents.

Copolymers of SMA

The first component of the resin of the present invention is one or more SMA copolymers. Copolymers of styrene and maleic anhydride are described, inter alia, in the Encyclopedia of Polymer Science and Engineering (Encyclopedia of Polymer Science and Engineering) volume 9 (1987), page 225. Within the scope of the present invention, the term "copolymer" likewise means SMA or a mixture of SMA's.

Useful Styrene and Maleic Anhydride (SMA) are type 1 SMA copolymers having a molecular weight in the range of about 1400 to about 50,000 and an anhydride content greater than 15 weight percent. Preferred are SMA copolymers having a molecular weight in the range of 1400 to 10,000. Examples of such copolymers include commercially available SMA1000, SMA 2000, SMA 3000, and SMA 4000. The styrene-maleic anhydride ratios of these copolymers are, for example, 1, 2; 8,1 and 9, and a molecular weight range of about 1400 to about 4000. Mixtures of these SMAs may also be used.

The amount of SMA copolymer used in the resin is from about 5 to about 40wt%, and more suitably from about 5 to about 30wt%, on a dry solids basis.

Epoxy resin

As used herein, the term "Epoxy resin" refers to curable compositions of oxirane ring-containing compounds as described in C.A., may, epoxy Resins, 2 nd edition, (New York & Basle: marcel Dekker Inc.), 1988.

Some examples of epoxy resins include: diglycidyl ethers based on bisphenol a; polyglycidyl ethers based on phenol-formaldehyde novolacs or cresol-formaldehyde novolacs; those based on triglycidyl ethers of tris (p-hydroxyphenyl) methane or on tetraglycidyl ethers of tetraphenylethane; amines such as those based on tetraglycidyl-methylenedianiline or on triglycidyl ether of p-aminoethylene glycol; alicyclic types, such as those based on 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate. The term "epoxy resin" also represents the reaction product of a compound containing an excess of an epoxy compound (e.g., of the type described above) and an aromatic dihydroxy compound. These compounds may be halogen substituted.

Preferred are epoxy resins, which are derivatives of bisphenol a, in particular FR4, in particular due to their low price. FR4 is prepared by the procession of an excess of bisphenol A diglycidyl ether with tetrabromobisphenol A. Mixtures of epoxy resins with bismaleimide resins, cyanate resins and/or bismaleimide triazine resins may also be applied.

It should be noted that epoxy resins are generally represented by a single, well-defined structural formula. One skilled in the art will appreciate that this should include off-products resulting from side reactions that occur during the preparation of the epoxy resin. Since these by-products constitute the normal constituents of cured epoxy resins, they likewise constitute the normal constituents of the resins according to the invention.

The resin includes one or more epoxy resins in a total amount of about 5wt% to about 50wt%, and more narrowly about 10wt% to about 40wt%, on a dry weight basis. In one aspect of the invention, the resin comprises two different epoxy resins.

Crosslinking agent

The resin will contain one or more cross-linking agents. Useful crosslinkers include brominated and non-brominated bisphenol a, brominated and non-brominated bisphenol a diglycidyl ether, tetrabromobisphenol a, and tetra-DOPO-bisphenol a. As noted above, each crosslinker may optionally be brominated, i.e., substituted with one or more bromine atoms. Brominated co-crosslinkers are useful for their flame retardant properties. Preferably, the aromatic moieties of BPA and BPADGE are each substituted with two bromine atoms to yield tetrabromo-TBBPA and TBBPADGE, respectively. Optionally, brominated novolacs may also be used as crosslinking agents.

The amount of crosslinker used in the resin is greater than about 0 to about 20wt%, and more narrowly about 0.05 to about 10wt%, based on solvent-free or solids.

Filler

The resins of the present invention include two or more different fillers. In general, the filler may be selected from fused silica, amorphous fused silica crystalline silica, fumed silica, talc, core-shell particles,

One or more of quartz, ceramic, particulate metal oxides in amorphous or crystalline form such as silica, titania, alumina, ceria, clay, calcined clay, boron nitride, wollastonite, particulate rubber, polyphenylene ether and mixtures thereof. Other examples of useful fillers include calcined clays, fused silica, and combinations thereof.

Particularly useful fillers are talc and silica, with fused silica and talc being particularly useful combinations. The first and second fillers are present in the resin in an amount of about 5wt% to about 50wt% on a dry resin basis, and more narrowly about 5wt% to about 37.5wt% on a dry resin basis, and most narrowly about 5wt% to about 25wt% on a dry resin basis.

When a combination of talc and silica is used in the resin, then talc should be present in an amount of about 2.5wt% to about 25wt% and silica should be present in an amount of about 2.5wt% to about 25 wt%. More narrowly, talc should be present in an amount of about 2.5wt% to about 15wt% and silica should be present in an amount of about 2.5wt% to about 15wt%, both based on dry resin. In an alternative embodiment, the weight ratio of silica or fumed silica to talc in the resin is from about 1.

One example of a useful talc is Microtuff AGD manufactured by Barretts Minerals, inc. The talc may be silane-treated or non-silane-treated. Further, the average talc particle size will be less than about 1.2 microns, preferably less than about 0.9 microns. Smaller talc particles can fill the resin voids in smaller amounts, and therefore the resin is less likely to expand upon heating.

An example of a useful silica filler is amorphous fused silica, particularly D ₅₀ Amorphous fused silica having a particle size of less than about 6.0 microns and more narrowly less than 4.0. In another example, the silica has a percolation threshold of 2-4 microns. It has been found that silica having a percolation threshold of 2-4 microns can enhance prepreg or PCB properties such as electrical properties, which begin to degrade as well as mechanical properties when silica having percolation thresholds outside this range are used. The silica may be silanized (silane treated) or non-silanized (non-silane treated). Silane treatment uses silanes and silazanes to chemically modify the silica (or talc) surface to make the surface hydrophobic.

Flame retardant

The compounded resins of the present invention may comprise one or more flame retardants. Any flame retardant known to be useful in resin compositions used in the manufacture of composites and laminates used in the manufacture of printed circuit boards may be used. The flame retardants may contain halogen or they may be halogen-free. Examples of useful flame retardants include, but are not limited to, halides of glycidyl etherified difunctional alcohols; novolac resins such as bisphenol a, bisphenol F, polyvinylphenol or phenol, cresol, alkylphenol, catechol, and halides of novolac resins; inorganic flame retardants such as antimony trioxide, red phosphorus, zirconium hydroxide, barium metaborate, aluminum hydroxide and magnesium hydroxide; and phosphorus-based flame retardants such as tetraphenylphosphine, trimethylphenol diphenyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, acid phosphate, ammonium polyphosphate, ammonium cyanurate, nitrogen-containing phosphate compounds, and halide-containing phosphate esters.

Phosphorus-based flame retardants may include, for example, those disclosed in U.S. Pat. nos. 6,645,631, 7,687,556, and 8,129,456, the respective specifications of which are incorporated herein by reference.

The flame retardant is present in the resin composition of the present invention in an amount sufficient to allow laminates made from the resin composition to pass the UL-94 flammability test. More narrowly, the flame retardant or combination thereof can be present in the resin in an amount of from about 5wt% to about 50wt%, or from about 10wt% to about 30wt%, on a dry weight basis.

In a preferred embodiment, the flame retardant is the solid flame retardant decabromodiphenylethane having the following structure:

decabromodiphenylethane is commercially available from, for example, albemarle Corporation (451 Florida St., baton Rouge, LA 70801). Albemarle product is expressed as Saytex ^TM 8010. Decabromodiphenylethane also unexpectedly improves the dielectric properties of the cured resin composition. Thus, decabromodiphenylethane can be included in the resin composition in an amount much greater than that required as a flame retardant in order to also improve the dielectric properties of the cured resin. Another useful high bromine content insoluble flame retardant is ethylene bistetrabromophthalimide, sold as Saytex BT93W by Albemarle Corporation. Other similarly useful flame retardants include decabromodiphenyl ether and brominated polystyrene.

Initiator/catalyst

The resin also contains an initiator/catalyst that facilitates crosslinking of the resin component, for example by performing various functions, such as facilitating homopolymerization and/or crosslinking of the resin component, and may be used to increase the rate at which the resin cures during thermal curing of the resin. The initiator/catalyst selected may be any compound known to be useful in resin synthesis or curing, whether or not it performs any of these functions.

Examples of useful initiators are azo-type initiators/catalysts, such as Azobisisobutyronitrile (AIBN), 2-propylimidazole (2-PI), tetrabutylphosphonium acetate (TBPAAc), and 2-methylimidazole (2-MI).

The amount of initiator used depends on the application. When used in the resin, the initiator is present in an amount in the range of about 0.01 to about 3.0 weight percent, more narrowly about 0.05 to about 1 weight percent.

In certain aspects, the resin generally comprises the ingredients in the amounts reported in table 1 below, where the amounts are reported on a solvent-free basis or on a solids-only weight basis.

TABLE 1

Alternative resin compositions are summarized in table 2 below, where the amounts of ingredients are reported in parts by weight including solvent.

TABLE 2

In one aspect, the invention includes a resin having the following composition, wherein the weight percent amounts are reported on a total solids (no solvent) basis:

1.10-40wt% of styrene maleic anhydride copolymer (SMA);

2.5 to 40 weight percent of an epoxy resin (brominated or non-brominated bisphenol A or a combination of bisphenol F);

3.0-20wt% of tetrabromobisphenol a or tetra-DOPO-bisphenol a;

4.5-20% of a halogen-containing or halogen-free flame retardant, such as a bromine or phosphorus-based monomer or resin;

5.5-40wt% of a filler combination (combination of two or more fillers) with the following possibilities: fused silica, crystalline silica, fumed silica, talc, clay, core shell rubber particles, or particulate flame retardants.

In another aspect, the invention includes a resin having the following composition, wherein the weight percent amounts are reported based on the total weight including solvent:

1.30% -40% solvent combination package of low boiling point and high boiling point solvents: methyl ethyl ketone, cyclohexanone;

2.15% -30% of styrene maleic anhydride copolymer (SMA)

3.10% -20% of an epoxy resin combination of brominated or non-brominated epoxy resins;

4.0.5% -10% of tetrabromobisphenol A or tetra-DOPO-bisphenol A;

5.5% -12.5% of talcum

6.5% -25% of fused silica

7.0.01% -0.03% of Tinopal OB (UV blocker) (optional)

8.0.01-0.13% tetrabutyl phosphonium acetate (TBPAAc), 2-methylimidazole (2-MI)

Or 2-phenylimidazole (2-PI).

Solvent(s)

One or more solvents are typically incorporated into the resin compositions of the present invention to dissolve the appropriate resin composition ingredients, and/or to control the resin viscosity, and/or to maintain the ingredients in a suspended dispersion. Any solvent known to those skilled in the art to be useful in conjunction with thermosetting resin systems may be used. Particularly useful solvents include Methyl Ethyl Ketone (MEK), toluene, dimethylformamide (DMF), acetone, propyl acetate, cyclohexanone, and combinations thereof.

When used, the solvent is present in the resin in an amount of about 20wt% to about 50wt% (weight percent) of the total weight of the resin composition including the solvent. Useful solvents are combinations of low boiling point solvents and high boiling point solvents, such as methyl ethyl ketone and cyclohexane.

Optional ingredients

(a) Toughening agent

The thermosetting resin composition of the present invention may compriseOne or more toughening agents. Toughening agents are added to the resin compositions to improve the drilling performance of the resulting composites and laminates. Useful toughening agents include methyl methacrylate/butadiene/styrene copolymers, methacrylate butadiene styrene core shell particles, and mixtures thereof. A preferred toughening agent is methacrylate butadiene styrene core shell particles, which are available under the trade name

From Rohm&Haas (100Independence Mall West, philadelphia, pa.). When used, the toughening agent is present in the thermosetting resin composition of the present invention in an amount of from about 1% to about 5%, preferably from about 2% to about 4%, based on 100% by weight of the solids of the composition.

(b) Other optional ingredients

Optionally, the compounded resin may also contain other additives such as defoamers, leveling agents, dyes, and pigments. For example, fluorescent dyes may be added in trace amounts to the resin composition so that laminates made therefrom are fluorescent when inspected with optical equipment when exposed to light. Useful fluorescent dyes are highly conjugated diene dyes. An example of such a dye is

OB (2, 5-Thienylbis (5-tert-butyl-1, 3-benzoxazole) available from Ciba Specialty Chemicals, tarrytown, new York.

Other optional ingredients known to those skilled in the art to be useful in resins used in the manufacture of printed circuit board laminates may also be included in the resin compositions of the present invention.

Prepregs and laminates of the invention prepared with a resin system comprising a combination of fumed silica and talc exhibit synergistically lower expansion under thermal stress and reflow, particularly when the amount of styrene in the SMA increases proportionally with anhydride. As the ratio of SMA space to anhydride increases, the expansion caused by the filler combination improves even more; when the ratio of anhydride to styrene is 1; 1; 1; 1; 1; 1.

In another aspect of the invention, the resin may comprise SMA in different proportions and different combinations of SMA. For example, a combination comprising two or more anhydride to styrene ratios (1, 4, 1. An extension of these filler combinations includes any filler type like talc, which consists of platelets combined with silica fillers of spherical or ellipsoidal or even porous shape. This would include any combination of these shaped fillers, such as shell rubber core particles that are generally spherical. Resins comprising this combination of fillers are more uniform and thus improve the thermal properties characteristic of laminates and prepregs used in the PCB industry. The industry has long-term thermal requirements that help prevent any delamination of the laminate within the printed circuit board. When incorporated into a laminate for a PCB, the resin comprising the combination of fillers disclosed above prevents delamination of the PCB in addition to reducing laminate expansion under thermal stress.

The combination of resin compositions including two different fillers results in a product that exhibits increased expansion with a greater proportion of space volume in the SMA system. This larger ratio is ideal for low dielectric constant performance, but this advantage results in increased expansion and thermal instability, which has been addressed in recent history by the use of silica fillers alone. The combination of two fillers in the resins described herein helps to reduce the expansion and thermal stability, particularly under thermal stress and reflow, and reduces the threat of delamination and/or white glass cracking and/or wicking.

Prepreg and laminate

The resins described above can be used to prepare prepregs and/or laminates for use in the manufacture of printed circuit boards. For use in the manufacture of printed circuit boards, the laminates may be partially cured or B-staged (in which case they are referred to as prepregs), in which state they may be stacked with other sheets of material and fully cured ("C-staged") to form a stack or PCB. Alternatively, the resin may be incorporated into a C-stage laminate, resin-coated copper plate, or interlayer sheet.

In one useful process, the resin is used to make prepregs in a batch or continuous process. Prepregs are typically manufactured using a reinforcing material, such as a woven glass mesh (fabric), which is spread into a series of driven rollers. The web is then transported to a coating zone where it is immersed in a bath containing a thermosetting resin containing a solvent, at which time the glass web is saturated with the resin. The resin-saturated glass web is then passed through a pair of metering bars or rollers to remove excess resin from the saturated glass web, and the resin-coated web is then advanced over the length of the drying tower for a selected period of time until the solvent evaporates from the web. By repeating these steps, an optional second and subsequent resin coat may be applied to the web until the preparation of the prepreg is complete, at which time the prepreg is wound up. The woven glass mesh may be replaced by woven fabric material, paper, plastic sheet, felt and/or particulate material such as glass fibre particles or particulate material.

In another method of making a prepreg or laminate, the thermosetting resin of the present invention is pre-mixed in a mixing vessel at ambient temperature and pressure. The viscosity of the pre-mix is about 600 to 1000cps and can be adjusted by adding solvent or removing solvent from the resin. The fabric substrate (typically but not limited to E-glass) is pulled through an impregnation tank containing pre-mixed resin, through an oven tower where excess solvent is removed and the prepreg is rolled or sheeted to size, stacked in various configurations between Cu foils (depending on the pattern of glass weave, resin content & thickness requirements).

The thermosetting resin (resin) mixture may also be applied in a thin layer onto a Cu foil substrate (RCC-resin coated Cu) using a slot die or other related coating technique.

Prepregs, laminates, resin-coated copper foils, and the like prepared using the resins described herein may be used to manufacture Printed Circuit Boards (PCBs) by using manufacturing techniques well known in the art.

In summary, embodiments of the present application include the following:

1. a resin composition comprising:

styrene maleic anhydride copolymers;

at least one epoxy resin;

at least one cross-linking agent;

talc; and

silicon dioxide.

2. The resin composition of clause 1, wherein the talc is present in the resin composition in an amount of about 2.5 to about 15wt% on a dry weight basis.

3. The resin composition of any of clauses 1-2, wherein the silica is present in the resin composition in an amount of about 2.5 to about 25wt% on a dry weight basis.

4. The resin composition according to any one of items 1 to 3, wherein the silica is fused silica.

5. The resin composition according to any one of items 1 to 4, wherein the silica is a silanized silica.

6. The resin composition of any of clauses 1 to 5, wherein the talc is a silanized talc.

7. The resin composition of any of clauses 1-6, comprising about 5 to about 12.5 weight percent talc and about 5 to about 25 weight percent silanized fused silica, each on a dry weight basis.

8. The resin composition of any of clauses 1-7, wherein the styrene maleic anhydride copolymer is present in the resin composition in an amount of about 5 to about 40 weight percent on a dry basis.

9. The resin composition of any of clauses 1-8, wherein the at least one epoxy resin is present in the resin composition in an amount of about 10 to about 50 weight percent on a dry weight basis.

10. The resin composition of any of clauses 1-9, wherein the at least one epoxy resin is selected from the group consisting of brominated bisphenol a, brominated bisphenol F, non-brominated bisphenol a, non-brominated bisphenol F, and combinations thereof.

11. The resin composition of any of clauses 1-10, wherein the at least one crosslinking agent is present in the resin composition in an amount of greater than 0 to about 20wt% on a dry weight basis.

12. The resin composition of any of clauses 1-11, wherein the at least one crosslinking agent is selected from tetrabromobisphenol a, tetra-DOPO-bisphenol a, and mixtures thereof.

13. The resin composition of any of clauses 1-12, comprising about 0.01 to about 3.0wt% of at least one azo-type catalyst on a dry weight basis.

14. The resin composition of any of clauses 1-13, including a catalyst selected from the group consisting of azobisisobutyronitrile, 2-propylimidazole, tetrabutylphosphonium acetate, 2-methylimidazole, and combinations thereof.

15. A resin composition comprising:

about 5 to about 40 weight percent, based on the dry, solvent-free resin, of a styrene maleic anhydride copolymer;

from about 10 to about 50wt%, based on dry, solvent-free resin, of at least one epoxy resin selected from the group consisting of brominated bisphenol a, brominated bisphenol F, non-brominated bisphenol a, non-brominated bisphenol F, and combinations thereof;

from about greater than 0 to about 20 weight percent, based on the dry, solvent-free resin, of at least one crosslinker selected from tetrabromobisphenol A, tetra-DOPO-bisphenol A, and mixtures thereof;

about 2.5 to about 15 weight percent talc; and

about 2.5 to about 15 weight percent fumed silica.

16. The resin composition of clause 15, wherein the weight ratio of fumed silica to talc is 1.

17. The resin composition of clause 15, wherein the weight ratio of fumed silica to talc is 1 to 2.5.

18. The resin composition of clause 15, wherein the fumed silica is an amorphous silanized fumed silica.

19. The resin composition of clause 15, wherein the talc is a silanized talc.

20. The resin composition of clause 15, wherein the crosslinker is a mixture of tetrabromobisphenol a and tetra-DOPO-bisphenol a.

21. The resin composition of clause 15, wherein the catalyst is tetrabutylphosphonium acid acetate.

22. A prepreg comprising a reinforcing material impregnated with the resin composition of any one of items 1 to 21.

23. A laminate comprising a reinforcing material and the resin composition of any of items 1-21, wherein the resin is C-staged.

24. A resin coated copper foil comprising a copper foil having a first planar surface and a second planar surface, wherein a layer of the resin of any of items 1-21 is applied to at least one of the planar surfaces, and wherein the resin is B-staged or C-staged.

25. The prepreg of item 22, wherein the prepreg is incorporated into a printed circuit board, and wherein the printed circuit board does not delaminate in an area of the prepreg.

26. The printed circuit board of item 25, wherein the IR 260 ℃ reflow wicking is 40 microns or less.

Examples

Resins with a single talc filler (ISE-S4) and with a filler comprising silica and talc (ISE-S3) were prepared according to the following formulation. The resins are used to make prepregs and laminates comprising glass fabric impregnated with the same type of resin. The prepregs and laminates were then used to prepare 24-layer multilayer printed circuit test boards having the specifications set out in table 3 below; a variety of properties were subsequently tested, including their ability to withstand delamination, their ability to withstand wicking, and their ability to withstand white glass cracking.

TABLE 3

In table 3, 1 × 2116rc57.8% means, for example, a prepreg having 1 layer of 2116 woven glass, and the Resin Content (RC) thereof is 57.8%.4mil H/H refers to a fully cured 4mm laminate made from 106 glass cloth with two resin coatings.

In addition to the two resins listed above, IS415, a commercially available SMA/epoxy prepreg (without any filler) was also used to prepare test panels as described in Table 3 above.

The ISE-S3 resin had the formulation set forth in Table 4 below.

TABLE 4

Including optional latex binder-1.7 wt%

UV-blocking agent-0.02 wt%

The printed circuit board under test is a test carrier comprising:

■ Various pitch sizes and BGA designs;

■ 24 layers, about 3mm thick, with 4 layers of 2 ounce copper;

■ The resin content was adjusted according to the density of the two variants, with the aim of maintaining the same volume of resin;

the ISE-S4 resin had a similar formulation except talc (11.6 wt%) was used throughout.

The IS415 resin has a similar formulation except that the filler IS omitted entirely.

The test results on the test vehicle show that:

■ ISE-S3 and ISE-S4 both performed well in terms of thermal performance after IR reflow at 6X 260 ℃.

However, ISE-S3 performs better than ISE-S4 in several important areas. ISE-S3 has:

■ Greater resistance to delamination

■ Reduction of white glass/cracking

■ Higher Tg at T288

■ ISE-S4 exhibits interconnect defects ICD, whereas ISE-S3 does not.

The results of the mechanical, thermal and electrical tests performed on each of the three test panels are listed in tables 5-7 below.

TABLE 5

TABLE 6

TABLE 7

Tables 6-7 detail the IR reflow test results at 260 degrees Celsius. IR reflow testing (infrared reflow soldering) of vias and ball grid arrays. Reflow testing showed that boards made using ISE-S3 prepreg and laminate showed wicking and white glass crack results consistently better than boards made from IS415 and ISE-S4 prepreg and laminate.

It should be noted that wicking is a measure of the distance copper migrates into the glass bundle adjacent to the plated through hole. Furthermore, reference to "cracking" or "white glass" in the above table refers to the amount of separation (distance) between the epoxy system and the individual glass fibers. When the cross-section is viewed microscopically, the cracks produce a silvery or white luster running down the individual glass fibers. The silvery luster results from air gaps around the individual glass fibers that reflect light.

Furthermore, after 6 x IR reflow testing at 260 ℃, the panels were cut and observed for cross-section and visually inspected for delamination, i.e. areas where adjacent layers of the prepreg or laminate had separated. The visual inspection results are reported in table 8 below.

TABLE 8 results of the hierarchical examination

BGA = ball grid array

The results of table 8 above show that the boards made with the laminate including the silica/talc filler combination showed no delamination after reflow testing in BGA and thermal via applications.

The resins and articles containing the resins have been described in detail hereinabove and with reference to the specific examples above; it will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. More specifically, although certain aspects of the present invention are identified herein as particularly advantageous, it is contemplated that the present invention is not necessarily limited to these specific aspects of the disclosure.

Claims

1. A resin composition comprising:

styrene maleic anhydride copolymers;

at least one epoxy resin;

at least one cross-linking agent;

talc; and

silicon dioxide.

2. The resin composition of claim 1, wherein the talc is present in the resin composition in an amount of about 2.5 to about 15wt% on a dry weight basis.

3. The resin composition of any of claims 1-2, wherein the silica is present in the resin composition in an amount of about 2.5 to about 25wt% on a dry weight basis.

4. The resin composition of any one of claims 1-2, wherein the silica is fused silica.

5. Resin composition according to any one of claims 1-2, wherein the silica is silanized silica.

6. The resin composition of any one of claims 1-2, wherein the talc is a silanized talc.

7. A resin composition comprising:

about 2.5 to about 15 weight percent talc; and

about 2.5 to about 15 weight percent fumed silica.

8. A prepreg comprising a reinforcing material impregnated with the resin composition of any one of claims 1-7.

9. A laminate comprising a reinforcing material and the resin composition of any one of claims 1-7, wherein the resin is C-staged.

10. A resin coated copper foil comprising a copper foil having a first planar surface and a second planar surface, wherein a layer of the resin of any one of claims 1-7 is applied to at least one of the planar surfaces, and wherein the resin is B-staged or C-staged.